SIGNIFICANCE OF SPONTANEOUS EPILEPTIFORM ABNORMALITIES ASSOCIATED WITH A PHOTOPAROXYSMAL RESPONSE

Spontaneous epileptiform abnormalities (SEAs) are reported to occur in up to 65% of patients with a photoparoxysmal response (PPR). Although the PPR is usually assumed to indicate primary generalized epilepsy, the clinical significance of associated SEAs is not known. We conducte d the first study designed to correlate seizure classification with ty pe of SEA in photosensitive patients. We examined seizure classificati ons and SEAs in 115 consecutive patients who had a PPR. A PPR was the only epileptiform abnormality in 47 patients (41%). Twenty-seven patie nts (24%) had focal SEAs and 41 (36%) had only generalized SEAs. Seven teen patients (15%) had partial seizures and 40 (35%) had only general ized seizures. Seizure classification was strongly associated with typ e of SEA ip < 0.0001). Patients with focal SEAs tended to have partial seizures, while patients with generalized SEAs tended to have only ge neralized tonic-clonic or absence seizures. Also, the presence of SEAs was significantly associated with a history of seizures (p < 0.0001), compared with patients who had a PPR but no SEAs. Although the PPR is often presumed to signify primary generalized epilepsy, most patients with a PPR and focal SEAs have partial seizures.